New, unopened, sealed package Kidde Worry-Free Smoke Alarm features a 10 year sealed battery (10 years from activation) that never needs changing Photoelectric sensor reduces false alarms Non-hardwired, battery operated. Voice Warning – Unit announces “Fire! Fire!” in addition to loud 85dB beeps when hazard is detected Tamper Resist Feature – Alarm will lock to mounting bracket to deter theft or tampering.